A further 1,400 Americans are awaiting a lung transplant. Finally, they transplanted the four lab-grown lungs into the four recipient pigs.

In research published this week in the journal Science Translational Medicine, the U of Texas researchers say they used a lung scaffold - literally the outer casing of lung tissue, called the extracellular matrix - and coated it with a concoction of growth factors and chemicals that stimulate the cells to turn into lung cells. Bioengineered organs are a hopeful solution to this problem, enabling needed organs to be engineered in a lab, then transplanted into the patient. After a month, the lungs were transplanted into the recipient pigs. Our ultimate goal is ultimately to provide new choices for the many people waiting for a transplant, "Nicole said".

The team accomplished this by creating a lung scaffold from the organ of another animal using both detergent and sugar to wipe out all the cells and blood - only the proteins were left.

On a "scaffold" in the laboratory, the appropriate cells were placed, which, after a 30 day culture, created a new lung.

The finished bioengineered lung - featuring cells from the patient - was then transplanted into the pigs. Animal recipients were survived for 10 hours, two weeks, one month and two months after transplantation, allowing the research team to examine development of the lung tissue following transplantation and how the bioengineered lung would integrate with the body.

Two months later, the lungs were still fully functioning and had 100 per cent oxygen saturation, meaning all their red blood cells were carrying oxygen through the body.

The study was meant to assess how well the bioengineered lungs adapted and continued to mature within a large, living body.

There was no signs of pulmonary edema, which is usually a sign of the vasculature not being mature enough, according to the researchers. As early as two weeks post-transplant, the bioengineered lung had established the strong network of blood vessels needed for the lung to survive.

"This project has taken 15 years to get to this point and we are thrilled that we did so well", Nichols said. Besides transplants, bioengineered lungs are a great testing medium for experimental drugs, another line of work that can save countless lives.